This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Sabrina McGary (Brougher) Surfactant Protein B Expression in Avian Lung The avian lung, which is structurally similar to mammalian upper airway, has been suggested as a novel model for human upper respiratory disease. Of particular interest are the surfactant proteins. The human alveolar surfactant proteins (SP-A, SP-B, SP-C and SP-D) are secreted by type 2 cells and function to reduce alveolar surface tension and modulate a localized immune response. The composition and function of surfactant in the upper airway is less well understood, yet it likely prevents the collapse of the bronchioles, and mediates inflammatory responses. The avian parabronchi (tubules which serve as the site of gas exchange) contain type 2 cells and have been shown to express SP-A and SP-B. Beyond this, little research has been conducted on avian lung. The goals of this project are (1) to characterize expression of the surfactant proteins in avian lung, and identify the embryonic age at which upregulation of expression occurs;(2) develop an in vitro culture system for avian embryonic lung explant tissue, and (3) develop a model for the isolation and differentiation of avian type 2 cells